In many applications where fluid is to be pumped it is desirable to use a disposable pump, for example in areas like the food and beverage industry or the medical sector where hygiene or sterility are important considerations. The most cost effective way to effect a disposable pump is to have a cheap disposable pump cartridge containing the pumping element and which contacts the fluid being pumped, and a non disposable pump driver that drives the pump cartridge.
Such pumps are commonly either peristaltic or pneumatically driven. Peristaltic pumps are quite effective but have limitations when it comes to pumping high viscosity fluids, such as beverage concentrates. Pneumatically driven pumps usually have a complex control system associated with them and rely of good sealing when the user initially puts the pump cartridge in the machine
In using such pumps the user must insert the disposable pump cartridge into the machine and ensure that it is properly engaged by the machine. This requires some level of skill from the user and is a potential area for failures to occur. In particular it is necessary to achieve a good seal between the pump and the machine for the pneumatic drive to function leak free.
Furthermore the disposable pump cartridges may be transported already attached to a reservoir of fluid. In this case it is important that should the pump and reservoir be dropped etc. during transport that none of the content of the reservoir should bleed out through the pump cartridge as a result of the hydrostatic pressures resulting from transportation.
The pump of the present invention may be used with a beverage dispenser as disclosed in International Application No. PCT/GB2008/000079 having an International Filing Date of Jan. 9, 2008, and for which a continuation-in-part U.S. National Stage application was filed as Serial No. on even date herewith, which PCT and continuation-in-part U.S. National Stage application are hereby incorporated by reference as though fully set forth herein.